This purpose of this project is to expand a web-based electronic data archive for the Tremin Trust Research Program on Women s Health. The web-accessible archive will preserve, in a stable format, data from one of the world?s oldest ongoing investigations of menstrual and reproductive health, and will make those data available to researchers worldwide. In the past 67 years the Tremin Trust, using prospectively recorded menstrual cycle calendars and annual health report surveys, has collected data on menstrual cycles and reproductive health born over 5000 women; there are currently 1,121 active participants in the study. Because it has been difficult to get access to and link together much of the Tremin Trust data, this rich resource has been under used. To make these data accessible to as many researchers as possible, the data must be cleaned, recoded, and relabeled, and the variables linked across the years of the study. Researchers must be provided with documentation about the data, and the process for gaining access to the data must be simplified. When completed, the website will allow qualified investigators to download the Tremin Trust data, including information on menstrual cycle characteristics, reproductive histories, health behaviors such as smoking, alcohol use, and exercise, stressful life events, health conditions, use of prescription drugs, surgeries, and the use of exogenous hormones. These data, collected across women?s reproductive lives, have the potential to provide information on how past menstrual patterns are linked to experience throughout and after the menopausal transition, to yield a better understanding of the variation in menstrual and menopausal experiences, to give new insight into patterns of reproductive aging, and to provide a basis for future studies of the health consequences of those patterns. This project will incorporate into the electronic archive the Tremin Trust data collected between 1934 and 1980; as part of a separate project, the web-based archive itself will be developed using the data collected since 1980.